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+EV poker; making the winning plays

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Saturday, November 8th, 2008 | Mark | Poker Articles, Poker Mathematics

This article is a part of the Poker Mathematics series.

This article is number 3 in a series of 3 articles covering the (in my opinion) most important mathematical aspects of poker:

Calculating pot odds: see Poker pot odds; all you need to know
Calculating poker probabilities: see Poker probabilities; all you need to know
Calculating expected value: see +EV poker; making the winning plays

Having explained how to calculate poker pot odds and poker probabilities in my two previous articles we now move on to applying these concepts to improve your poker game by making the winning plays every time. The concept you will need to learn is EV, which is short for expected value.

In poker, EV is a measure of how much you will be payed back on average on a 1$ bet:

EV < 1 - If you always play hands with an EV of less than 1 you will lose on average
EV = 1 - If you always play hands with an EV equal to 1 you will break even on average
EV > 1 - If you always play hands with an EV of more than 1 you will win on average

Needless to say it should be the goal of any poker player to make plays that always belong to the EV > 1 category.

When it comes to calculating your EV for any given poker hand that the European decimal odds system that I favour excels.

Simply multiply the decimal pot odds you are given by the probability that you will win the hand, and you have your EV. Simple as that.

When using the European decimal odds system it is also easy to calculate either the pot odds or probability needed to break even (EV = 1) from the following relationships:

pot odds = 1/Probability
probability = 1/pot odds

Here are some examples of how these calculations work in real situations:

You have 15 outs on the turn to win the hand and you have to call 700 into a 1500 pot. What is your EV for the given situation? Well the probability for winning the hand is (15*2+1)% = 31% = 0,31 using the easy rule of thumb. Your decimal pot odds are (1500+700)/700 = 3,14. This gives an EV of 3,14*0,31 = 0,97. Therefore you will on average lose 3 cents for every dollar you bet by making this call.
In the example from above, what decimal pot odds do you need to break even? The answer is 1/0,31 = 3,23.
You are holding a pair of eights and the flop is high cards. To win the hand you need to hit a set on either the turn or the river. What pot odds do you need on the turn and the river in order to break even? Again using the easy rule of thumb the probability of hitting your set on the turn is (2*2+1)% = 0,05, so you need a pot odds of 1/0,05 = 20 in order to break even. The same applies to the river.

Even though these calculations are straightforward you will need some practice to be able to perform them fast enough at the poker tables. Therefore you might want to make a set of guidelines to memorize. The list below will get you started:

If your single opponent bets the pot on the flop your pot odds are 3 for calling to see the turn card. Therefore you need a probability better than 33% to make the call and win in the long run. This corresponds to approximately 16 outs.
If your single opponent bets half the pot on the flop your pot odds are 4 for calling to see the turn card. Therefore you need a probability better than 25% to make the call and win in the long run. This corresponds to approximately 12 outs.
When you flop a flush draw and want to see a turn card you need pot odds 5,2 to break even.

For those of you using the fractional odds system I would recommend that you convert your pot odds to the decimal system when calculating your EV values. For conversion between the European decimal odds system and the UK fractional odds system see poker pot odds; all you need to know.

Having now covered the basics of the poker mathematics essentials I will move on to the more advanced concepts of implied and reverse implied odds in later articles.

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